Narrative:

I was cleared to fly the jammn arrival except to cross puutt at 9000 ft (instead of 11000 ft as published). Runway 16 was the active so the 'landing south' portion of the arrival was the information I was following. I crossed gronk at 13000 ft (as depicted) at 30 DME then began a descent to 12000 ft to cross chipp at 12000 ft. Due to the way the arrival plate is drawn, I missed/overlooked the fact that I wasn't to begin my descent until spiek, 7 mi later at the 23 DME fix. Passing 12600 ft, approach control called and said I had descended early and to maintain 13000 ft. That was my first indication that something was wrong. I climbed back to 13000 ft until 23 DME and continued the remainder of the arrival. I called approach when I landed and discussed the confusion on the arrival. They said I was not the first to make that mistake. I told them I would discuss the confusion aspect with my chief pilot, which I did. Comments: my flight operations had put out a 'read before fly' note regarding the jammn arrival because we had so many complaints about pilots descending early. I had read it, was aware of the problem, yet fell into the same trap. Both 'landing north' and 'landing south' information is presented as boxed items adding to the confusion. The boxed items contain information for multiple fixes with as many as 3 arrows pointing to fixes not adjacent to the boxes. The top most box contains information in reverse order to the fixes to be crossed. You are 'forced' to fly heads down in the cockpit to insure the arrival is flown properly. In the very busy terminal area of slc this is not conducive to a safe operation.

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Original NASA ASRS Text

Title: AN ACR FLC ON THE JAMMN 1 STAR DSNDS BELOW 13000 FT BEFORE XING SPIEK. THE APCH CTLR CORRECTS THE CREW IMMEDIATELY.

Narrative: I WAS CLRED TO FLY THE JAMMN ARR EXCEPT TO CROSS PUUTT AT 9000 FT (INSTEAD OF 11000 FT AS PUBLISHED). RWY 16 WAS THE ACTIVE SO THE 'LNDG S' PORTION OF THE ARR WAS THE INFO I WAS FOLLOWING. I CROSSED GRONK AT 13000 FT (AS DEPICTED) AT 30 DME THEN BEGAN A DSCNT TO 12000 FT TO CROSS CHIPP AT 12000 FT. DUE TO THE WAY THE ARR PLATE IS DRAWN, I MISSED/OVERLOOKED THE FACT THAT I WASN'T TO BEGIN MY DSCNT UNTIL SPIEK, 7 MI LATER AT THE 23 DME FIX. PASSING 12600 FT, APCH CTL CALLED AND SAID I HAD DSNDED EARLY AND TO MAINTAIN 13000 FT. THAT WAS MY FIRST INDICATION THAT SOMETHING WAS WRONG. I CLBED BACK TO 13000 FT UNTIL 23 DME AND CONTINUED THE REMAINDER OF THE ARR. I CALLED APCH WHEN I LANDED AND DISCUSSED THE CONFUSION ON THE ARR. THEY SAID I WAS NOT THE FIRST TO MAKE THAT MISTAKE. I TOLD THEM I WOULD DISCUSS THE CONFUSION ASPECT WITH MY CHIEF PLT, WHICH I DID. COMMENTS: MY FLT OPS HAD PUT OUT A 'READ BEFORE FLY' NOTE REGARDING THE JAMMN ARR BECAUSE WE HAD SO MANY COMPLAINTS ABOUT PLTS DSNDING EARLY. I HAD READ IT, WAS AWARE OF THE PROB, YET FELL INTO THE SAME TRAP. BOTH 'LNDG N' AND 'LNDG S' INFO IS PRESENTED AS BOXED ITEMS ADDING TO THE CONFUSION. THE BOXED ITEMS CONTAIN INFO FOR MULTIPLE FIXES WITH AS MANY AS 3 ARROWS POINTING TO FIXES NOT ADJACENT TO THE BOXES. THE TOP MOST BOX CONTAINS INFO IN REVERSE ORDER TO THE FIXES TO BE CROSSED. YOU ARE 'FORCED' TO FLY HEADS DOWN IN THE COCKPIT TO INSURE THE ARR IS FLOWN PROPERLY. IN THE VERY BUSY TERMINAL AREA OF SLC THIS IS NOT CONDUCIVE TO A SAFE OP.

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.